Tone amplifier



M. CLARK TONE AMPLIFIER Feb. 7, 1933.

Filed March 30, 1951 212 TOR} WIT/vs. & 7, QVaZ/nd/ Patented Feb. 7, 1933 MELVILLE CLARK, OF SYRACUSE, NEW YORK TONE AMPLIFIER Application filed March 30, 1931. Serial No. 526,302.

This invention relates to an apparatus for converting the vibrations of any vibratory element or elements into electrical impulses and translating said impulses into sound, and is particularly useful in amplifying the tones of musical instruments either individually or in various combinations.

It is well known that the volume of the tones of many of the smaller instruments,

while sufficient for pleasing effects in the relatively small rooms of private houses and auditoriums, is frequently insufiicient in the larger concert halls and the like, and that this is particularly true when these instru- 5 ments are played in concert or orchestral renditions.

The main object of the present invention is to provide simple and highly efficient means for electrically converting the vibra- 3 tions of the sounding board or other vibratory element of a musical instrument into corresponding sounds, amplifying said sounds and controlling the volume of the electrical impulses in transit to the amplifying means.

One of the specific objects is to convert the vibrations of any vibratory element into electric impulses through the medium of an instrument technically known as an electric pickup and rigid connections between its armature and the vibratory element so that the frequency and instensity of the electric pulsations will exactly correspond with the frequency and amplitude of vibrations of the vibratory element, thereby reducing to a minimum the liability of electric impulses which are out of harmony or synchronism with such vibrations.

Another object is to enable the vibrations of a plurality of vibratory elements to be simultaneously or selectively translated into sound through the medium of a single sound translating device common to all of said elements.

In other Words I have sought to provide a more convenient and practical means for amplifying and controlling the amplification of the tones of any one or more musical instruments in solo, accompaniment or orchestral renditions than has heretofore been practised.

Other objects and uses relating to specific parts of the apparatus and to the method of using the same will be brought out in the following description.

In the drawing Figure 1 is a diagrammatic view of my improved tone amplifying apparatus as used in connection with a plurality of vibratory elements for selected and group control of the translation of the vibrations of any one or more of said elements into sound.

Figure 2 is a perspective view of a portion of a relatively small Irish harp with an electrio pickup operatively mounted thereon, and the rigid connections between the needle of the pickup and the sounding board or vibrating element of the harp.

igure 3 is an enlarged face view of the electric pickup and adjacent portion of the frame of the harp showing in section the rigid connection between the armature of the pickup and sounding board of the harp, taken in the plane of line 33, Figure 2.

In order that the range of use of the apparatus may be clearly understood I have shown in Figure 1 a plurality of, in this instance three, vibratory elements A and a corresponding number of electric pickup devices 1, each having its armature or vibrator 2 rigidly connected to the corresponding element A through the medium of a screw-threaded connector rod 3 egaging an internally threaded sleeve or bushing 4 which is also threaded externally and screwed tightly into the vibrating element A-, as shown more clearly in Figure 3, the rod 3 and sleeve 4 being rigidly held against relative move-' ment by a lock nut 5 engaging the threaded portion of the bolt and outer end of the sleeve.

The vibrating member A is shown as consisting of a sounding board of a relatively small harp A- having the usual strings a.

Each pickup l is detachably mounted upon a supporting bracket B which in turn is secured by screws or equivalent fastening means as b to the non-vibratory body of the instrument such as the harp A- 100 for rigidly supporting the pickup device in spaced relation thereto with its needle 2 arranged to vibrate in aplane at substantiall right angles to that of the sounding boar the connecting rod 3 being arranged at substantially right angles to the needle 2- so that the vibrations of the sounding board will be transmitted directly to the vibrator of the pickup device for converting such vibrations into electrical impulses.

The means for securing the pickup device 1 to the bracket B- preferably consists of a threaded stud or bolt C secured to one of the side walls of the pickup device to extend through an elongated slot -b in the bracket B- and having its outer threaded end engaged by a thumb nut -c and washer c which, when released, enables the pickup device to be removed from the bracket by lateral displacement through a branch slot b in the bracket, as shown in Figure 3.

Each pickup circuit as 6 includes therein an electric switch 7, a local selective volume control 8, preferably in the form of a potentiometer rheostat, and a more or less remote selective volume control 9, preferably in the form of aseries rheostat, all of said circuits 6 being electrically connected to a single conventional loud speaker 10 through the medium of a conventional vacuum tube 1 amplifier 11 and total volume control device 12, as shown in Figure 1.

The several vibratory members A may represent similar or different musical instruments of an orchestra or a group of such instruments, the players of which are under the control of a director, stationed at D or in proximity to the several switches 7, selective control device 9 and total volume control device 12, while the several volume control devices 8 may be positioned in proximity to the players of the corresponding instruments represented by the vibratory elements Under this arrangement the individual ,players may regulate the volume or intensity of the electric impulses in the corresponding circuits 6 through the medium of the adjacent volume control devices 8, while the director at the station -D may selectively control the volume of the several instruments through the medium of the switches 7 and selective volume control device 9, and may also control the total volume of the selected instrument or instruments through the medium of the rheostat 12.

For example, when any one or more of the instruments represented by the vibratory members A- are being played and the corresponding switch or switches 7 are closed, the vibrations of the elements A will be converted by the corresponding pickup device or devices into electrical impulses which will be transmitted over the corresponding asaaees circuit or circuits to the loud speaker 10 through the medium of the vacuum tube amplifier 11 for translating the impulses into sound corresponding exactly to the vibrations of the vibratory element or elements A.

The several switches 7 are under the control of the director and are operable individually or collectively, thus ermitting the director to cause the ampli cation of the sound produced by any one or more of the instruments by simply closing the correspondin switch or switches 7.

n like manner the total tone volume of the several instruments either individually or in different combinations, may be regulated by the director through the medium of the rheostat 12, or variations in the tone volume of the several instruments may be regulated by the director through the medium of the series rheostat 9 independently of the several players.

It is evident, however, that the player of any one of the instruments may control the tone volume of that particular instrument by proper adjustment of the corresponding rheostat 8.

Although I have shown the apparatus as applicable to the vibratory elements of any number of musical instruments for orchestral renditions, it is obvious that it is equally iJ applicable to the vibratory element of a single instrument for solo renditions, in which case the corresponding switch 7 and any one or more of the volume controlling devices 8, 9

and 12 would be arranged within easy reach-' ing distance of the player.

Operation Assuming that any one of the instruments represented by the vibratory element A is being played and that the volume of its tones is insufficient to carry to remote parts of the room in which the instrument is located and that it is desirable to amplify those tones, then it is simply necessary to close the corresponding switch 7 and allow the current impulses produced by the operation of the pickup device 1 to be transmitted to the loud speaker 10 through the medium of the vacuum tube amplifier 11,

thereby greatly increasing the tone volume of the instrument to a degree sufficient to carry it to remote parts of the hall or room in which the instrument is located, it being understood that the intensity of the pulsations and resultant amplifications of the translated sound may be regulated by a proper adjustment of the rheostat 12 and by any one or both of the rheostats 8 and 9.

One of the important features of the invention, however, lies in the use of a rigid connection such as the rod or bar 3 between the pickup vibrator 2 and vibrating member as -A- of a musical instrument or other vibrating member, the vibrations of which are to be converted into electrical impulses and translated into sound, but obviously various changes may be made in the manner of mounting the pickup device upon the frame of the instrument and also in the means for rigidly connecting the vibrator 2 to the vibrating member without departing from the spirit of the invention.

When this pickup device is used in the conversion and translation of vibrations of widely varying frequency and amplitude it is preferably connected to that part of the vibrating element having the higher frequency of vibration as, for example, adjacent that part of the sounding board of a harp to which the shorter strings are connected, as shown in F igare 2.

The invention, however, contemplates the use of this electrical pickup device in connection with any kind of string instrument, percussion instrument, wind instrument and, in fact, any vibratory element operable directly or indirectly through the medium of mechanical means or by the movements of air currents or columns.

For example, when the electric pickup is used in connection with the piano it Will be mounted upon some portion of the interior frame adjacent the sounding board so that its vibrator may be rigidly connected to said sounding board to convert the vibrations thereof into electrical impulses.

When used in connection with the violins, cellos, bass viols and analogous instruments having bridges across which the strings are tightened the pickup device will be applied to the bridge, while in banjos, guitars and similar instruments it may be applied to the vibratory body or frame, and when used in connection with moving air columns, a suitable vibratory member may be placed in such manner as to be readily responsive to the movements of the air, in which case the pickup device will be attached directly to said vibratory member.

What I claim is The combination with a harp, of an electric pick-up device supported independently of the sounding board and having its vibratory element rigidly connected to the sounding board of the harp at a point nearer to the neck than to the base of the harp.

In witness whereof I have hereunto set my hand this 11th day of March, 1931.

MELVILLE CLARK. 

